What's the best Android app for sending invoices and tracking payments on the go?

QuickBooks Online Accounting is a mobile extension of the widely-used accounting platform, designed specifically for small business owners and freelancers who need to manage finances outside the office. For the task of sending invoices and tracking payments, the app provides a streamlined workflow. Users can generate new invoices, customize them with line items and taxes, and email them directly to clients. A significant feature is the ability to attach PDF copies of invoices, though some recent reviews indicate a recurring bug where the app intermittently fails to handle PDF generation for email, prompting users to install a separate viewer. When functioning correctly, the payment tracking is robust, showing a clear dashboard of sent, viewed, and paid invoices. Users can also record payments received via cash, check, or linked payment processors, with all data syncing instantly to the cloud-based account. This is particularly useful for a contractor finishing a job site visit who can issue an invoice before leaving the client's property. The app's mileage tracking and receipt capture features further support on-the-go expense management. However, some users note a desire for more visibility into sent estimates without requiring client interaction first. While the core functionality is strong for mobile invoicing and payment status, occasional app-specific glitches can interrupt the PDF workflow, suggesting a need for consistent updates from the developer.